Extracting summary statistics to perform meta-analyses of the published literature for survival endpoints

Meta-analyses aim to provide a full and comprehensive summary of related st udies which have addressed a similar question. When the studies involve tim e to event (survival-type) data the most appropriate statistics to use are the log hazard ratio and its variance. However, these are not always explic itly presented for each study. In this paper a number of methods of extract ing estimates of these statistics in a variety of situations are presented. Use of these methods should improve the efficiency and reliability of meta -analyses of the published literature with survival-type endpoints. (C) 199 8 John Wiley & Sons, Ltd.